TEAS Science Practice Test 2 — Questions and Answers
Question 1: Which of the following best describes the function of the mitochondria in a cell?
- Protein synthesis and folding
- Cellular energy production through ATP generation (Correct answer)
- Storage of genetic material and cell division
- Detoxification of harmful substances
Correct answer: Cellular energy production through ATP generation
Mitochondria are the powerhouses of the cell, responsible for producing ATP through cellular respiration (oxidative phosphorylation).
Mitochondria are double-membrane organelles that generate most of the cell's supply of adenosine triphosphate (ATP) through oxidative phosphorylation. During cellular respiration, glucose and oxygen are converted into ATP, carbon dioxide, and water. The inner mitochondrial membrane contains the electron transport chain where the majority of ATP is produced. Protein synthesis occurs at ribosomes, genetic material is stored in the nucleus, and detoxification primarily occurs in the smooth endoplasmic reticulum and liver cells.
Question 2: A patient's blood test shows a pH of 7.30. Which of the following conditions does this indicate?
- Alkalosis
- Acidosis (Correct answer)
- Normal blood pH
- Neutral pH
Correct answer: Acidosis
Normal blood pH is 7.35-7.45. A pH of 7.30 falls below this range, indicating acidosis (excess acid in the blood).
Normal arterial blood pH ranges from 7.35 to 7.45. A pH below 7.35 indicates acidosis—a condition where there is too much acid in the body fluids. At 7.30, this patient has acidosis, which could be respiratory (from CO2 retention) or metabolic (from bicarbonate loss or acid accumulation, such as in diabetic ketoacidosis). Alkalosis occurs when pH exceeds 7.45. Even small deviations from normal pH can significantly affect enzyme function and cellular processes.
Question 3: During inhalation, what happens to the diaphragm and thoracic cavity?
- The diaphragm relaxes and the thoracic cavity decreases in volume
- The diaphragm contracts and flattens while the thoracic cavity expands (Correct answer)
- The diaphragm contracts and rises while the thoracic cavity decreases
- The diaphragm relaxes and the thoracic cavity remains the same size
Correct answer: The diaphragm contracts and flattens while the thoracic cavity expands
During inhalation, the diaphragm contracts and flattens, increasing the volume of the thoracic cavity and creating negative pressure that draws air into the lungs.
Inhalation (inspiration) is an active process. The diaphragm, a dome-shaped muscle at the base of the thoracic cavity, contracts and moves downward, flattening out. Simultaneously, the external intercostal muscles contract to lift the rib cage upward and outward. These actions increase the volume of the thoracic cavity, decreasing intrapulmonary pressure below atmospheric pressure (creating negative pressure), which causes air to flow into the lungs according to Boyle's law. Exhalation at rest is largely passive as these muscles relax.
Question 4: Which type of chemical bond involves the sharing of electron pairs between atoms?
- Ionic bond
- Covalent bond (Correct answer)
- Hydrogen bond
- Metallic bond
Correct answer: Covalent bond
Covalent bonds form when atoms share one or more pairs of electrons, as opposed to ionic bonds where electrons are transferred from one atom to another.
Covalent bonds form when two atoms share one or more pairs of valence electrons. This typically occurs between nonmetal atoms with similar electronegativities. Examples include O₂ (double covalent bond), H₂O (polar covalent bonds), and organic molecules like glucose. Ionic bonds involve the transfer of electrons (e.g., NaCl). Hydrogen bonds are weak intermolecular attractions between a hydrogen atom bonded to an electronegative atom and another electronegative atom. Metallic bonds involve a 'sea of electrons' shared among metal atoms.
Question 5: The sympathetic nervous system is activated during a 'fight or flight' response. Which of the following is a physiological effect of sympathetic activation?
- Decreased heart rate and blood pressure
- Constriction of bronchioles in the lungs
- Increased peristalsis in the digestive tract
- Dilation of pupils and increased heart rate (Correct answer)
Correct answer: Dilation of pupils and increased heart rate
Sympathetic activation prepares the body for action by dilating pupils (to improve vision), increasing heart rate (to deliver more blood to muscles), and redirecting blood flow away from digestion.
The sympathetic nervous system prepares the body for 'fight or flight' through several coordinated responses: pupil dilation (mydriasis) to improve visual acuity, increased heart rate and contractility to boost cardiac output, bronchodilation to increase air flow, redirection of blood to skeletal muscles, increased blood glucose through glycogenolysis, and decreased digestive activity. The parasympathetic nervous system ('rest and digest') has opposite effects—it decreases heart rate, constricts pupils, and increases peristalsis.
Question 6: In an experiment, a scientist tests whether a new fertilizer increases tomato plant growth. The plants given fertilizer are the experimental group. What is the control group?
- Plants given twice the amount of fertilizer
- Plants grown in a different location
- Plants grown under identical conditions but without the fertilizer (Correct answer)
- Plants of a different species grown with the fertilizer
Correct answer: Plants grown under identical conditions but without the fertilizer
The control group must be identical to the experimental group in every way except for the independent variable (fertilizer), so it consists of plants grown under the same conditions without fertilizer.
In a controlled experiment, the control group serves as the baseline for comparison. It must be treated identically to the experimental group in all respects—same soil, water, light, temperature, plant variety, and pot size—except for the independent variable being tested (in this case, the fertilizer). This ensures that any observed differences in growth can be attributed to the fertilizer rather than other factors. Using different locations, species, or doubled amounts would introduce confounding variables that compromise the experiment's validity.
TEAS Science Practice Test 2
Which of the following best describes the function of the mitochondria in a cell?